Genus: Planktonic; colony of 4 cells; cell body crescent in shape, both ends pointed; four cells radially arranged by attaching at the outward mid-region; a single chloroplast plate-like in shape, slightly curved, with a pyrenoid (Guide book to the "Photomicrographs of the Freshwater Algae", 1998). Species: Colonies of 4 (or 2 or 8) cells, free-floating; cell body crescent in shape, both ends pointed, 4-5 μm wide, 12-18 μm long; cells attached each other at their convex side, arranging parallel in side view, and radial in top view; a single chloroplast parietal, plate-like, with a pyrenoid (Photomicrographs of the Fresh-water Algae, vol. 1, 1984).

50 μm 100 μm 150 μm; x 400 : 31 μm 63 μm 94 μm; x 640

Tetradesmus wisconsinensis G.M. Smith: Colonies of 4 (or 2 or 8) cells, free-floating; cell body crescent in shape, both ends pointed, 4-5 μm wide, 12-18 μm long; cells attached each other at their convex side, arranging parallel in side view, and radial in top view; a single chloroplast parietal, plate-like, with a pyrenoid (Photomicrographs of the Fresh-water Algae, vol. 1, 1984).